Grinding machine



Feb. 19, 1935. s. EINSTEIN El AL GRINDING MACHINE Filed Dec. 27, 1932 4 Sheets-Sheet 1 Feb. 19, 1935. 5, E|N5TE|N 7 1,991,799

GRINDING MACHINE Filed Dec. 27, 1932 4 Sheets-Sheet 2 a la gwumdw 15 S01. Einste'm Clemerdf Boo ch Feb 19, 1935. 5. m; H AL 1,991,799

. GRINDING MACHINE Filed Dec. 2'7, 1 932 4 Sheets-Sheet 3 S 01. gins cein Clemenc Bo'zflzh Feb. 19, 1935. S N TE 1,991,799

GRINDING MACHINE Filed Dec 2'7, 1932 4 Sheets-Sheet 4 Fi elO 3mm Sol Einsiein Clemerfi Boo Patented Feb. 19, 1935 GRINDING MACHINE Sol Einstein and Clement Booth, Cincinnati, Ohi

asrignors to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application December 27, 1932, Serial No. 648,844

26 Claims.

This application is a continuation, in part, of the applicants prior copending application Serial No. 350,679, filed March 28, 1929.

The present invention relates to grinding ma- 5 chines and particularly to a machine in which the size of the workpiece is determined and controlled by a gauge member which contacts the periphery of the grinding wheel.

In prior devices of this character, the size of the workpiece has been determined, in general, by a sizing device which contacts the surface of the workpiece on which the grinding operation is being performed, or, in internal grinding, the size is determined by a gauge member which is ar- 1 ranged to enter the bore of the workpiece when the latter is ground to the desired size. Although this method of controlling the size of the workpiece is entirely satisfactory in ordinary grinding operations, it is necessary to replace the gauge frequently as a result of the wear thereon. Gauging of internally ground workpieces which are supported and rotated on the periphery thereof during the grinding by a gauge which enters the bore of the workpiece is also not practical if the successive workpieces vary somewhat in outside diameter since, in this case, the gauge is not in line with the bore of the workpiece.

In the type of grinding where the gauge member is positioned in contact with the surface of the workpiece in order to determine accurately the size of the work, said member should engage the surface of said workpiece along the same element of the workpiece that is in engagement with the grinding wheel, but, when this is attempted, the gauge member interferes with the proper operation of the grinding wheel, as will be'apparent. Accordingly, prior art machines have necessarily mounted the gauging member for engagement with the workpiece at a point spaced from the point of engagement of the grinding wheel with said workpiece. In centerless grinding of internal workpieces, with a gauge contacting the surface of the workpiece remote from the point of engagement between the workpiece and the grinding wheel, the completed internal bore of the workpiece varies in size in accordance with the variations in diameter of the external surface of said workpiece upon which surface the latter is supported and rotated. One of the principal objects of the present invention is, accordingly, to provide a sense by which successive workpieces may be internally ground with each successive workpiece having the same wall thickness independently of the external diameter of the workpiece. A further object is to provide for accurate gauging of the size of a workpiece by a gauge member which contacts the grinding wheel, the member which is subject to wear, a. gauge of this type operating independently of the wear on the grinding wheel.

A further object is to provide a gauge which is in contact with the grinding wheel only momentarily, the contact with the grinding wheel operating to withdraw said gauge away from the wheel and to procure a change in the grinding operation. This type of gauge, since it is subjected to only a momentary contact with the grinding wheel at the time when the workpiece reaches the desired finish size, is not subject to appreciable wear during the grinding operation 15 and will therefore retain its accuracy over a longer period of time than in the usual gauge members which are in continual contact with the workpiece during the entire grinding operation. 29

Other and further objects and advantages of the invention will appear from the following detailed description in connection with the accompanying drawings in which:

Fig. 1 is a front view of a grinding machine embodying the invention.

Fig. 2 is a plan view of the machine of Fig. 1.

Fig. 3 is a vertical section substantially along the line 3-3 of Fig. 1.

Fig. 4 is a horizontal section substantially along the line 44 of Fig. 3.

Fig. 5 is a plan view of the supporting structure for the gauge.

Fig. 6 is a vertical section substantially along the line 66 of Fig. 5.

Fig. 7 is a vertical section substantially along the line 7-7 of Fig. 5.

Fig. 8 is a section substantially along the line 8-8 of Fig. 6.

Fig. 9 is a fragmentary elevation with parts broken away to show the clutch for the crossfeed mechanism.

Fig. 10 is a wiring diagram.

Fig. 11 is a modified wiring diagram.

Fig. 12 is an elevation of a grinding machine showing a modification.

Fig. 13 is a vertical section substantially along the line 1313 of Fig. 12.

Like reference characters refer to like parts throughout the drawings.

Referring first to Figs. '1 and 2, the machine comprises a base 1 having onits upper surface horizontally spaced ways 2 and 3. A grinding wheel carriage 4 is supported on the ways 2 for reciprocation longitudinally of the base and supwheel spindle 6 is mounted, the latter being rotated by a motor 7 also mounted on the slide.

. The grinding wheel 8 is given a constant reciprocation of a predetermined length by any suitable mechanism as, for example, the fluid pressure actuated mechanism disclosed in the Heald and Guild Patent No. 1,582,468. The limits of reciprocation are determined by spaced adjustable reversing dogs 9 and 10 on the slide which alternately engage and rock a reversing lever 11 which, in any suitable manner, reverses the, direction of movement of the slide.

A work supporting carriage 12 is mounted for longitudinal reciprocatory' movement on the ways 3 and supports thereon a cross-slide 13 on which is mounted a centerless work-supporting member 14. The latter comprises a regulating wheel 15 (see Fig. 3) mounted for rotation on the crossslide, a work rest or blade 1'7, beneath and forwardly of the center of the regulating wheel and 'adjustably mounted on the cross-slide, and a pressure wheel 18, the axis 19. on which said wheel 18 is journaled, being normally slightly above and forwardly of the regulating wheel, said work rest 17 and the regulating and pressure wheels all engaging the periphery of the workpiece a so the latter is supported on its external surface. The pressure wheel is normally urged against the workpiece to maintain the latter in proper position in engagement with the regulating wheel and the work rest, and is pivotally supported by links 20 for movement toward and away fromthe regulating wheel to permit removal of the workpiece from within the worksupport and placing of an unground workpiece therein.

The longitudinal movement of the work-supportingslide is procured in any suitable manner, as by fluid under pressure and the limits of movement of said carriage are determined by the spaced dogs 21 and 22 on the front of said carriage, said dogs determining the operative grinding position and the non-grinding or rest position of the carriage. The latter is moved from the inoperative position shown in which the workpiece thereon is axially spaced from the grinding wheel, into operative position in which the grinding wheel is located within the Bore of the workpiece, where the carriage is brought to rest by engagement of the dog 21 with the pivotally mounted lever 23. Said lever is connected by a link 24 to the lever 25 by which the fluid for shifting the work-supporting carriage is controlled. The dog 21, during the movement of the carriage into operative position, thus shifts the lever 25 into neutral position to bring the carriage to rest in grinding position, and said carriage remains in operative position until the lever 25 is again shifted to return the carriage to inoperative position. Upon the return movement of the carriage to inoperative position, the dog 22 procures movement of the lever 25 again to neutral position, bringing the carriage to res in the inoperative position shown.

Referring now to Fig. 4, the regulating wheel 15 is carried on the end of a shaft 26 journaled in a housing 27 on the cross-slide, and the shaft 26 carries a worm gear 28 which engages the worm 29 on a vertical shaft 30 journaled in the cross-slide, the rotation of said shaft 30 procuring rotation of the regulating wheel and accordingly a corresponding rotation of the workpiece which is in engagement therewith. The shaft 30 is suitably connected to a driving motor, not shown.

The crossfeed mechanism for the work-supporting member, by which to procure a radial feeding movement between the grinding wheel and the workpiece, is best shown in Fig. 3. Referring to this figure, the cross-slide 13 has an internally threaded lug 31 therein for engagement with the crossfeed shaft 32, the forward end of which projects into and is journaled in a housing 33 on the front of the work-supporting carriage 12. A gear 34 on the forward end of said crossfeed shaft meshes with an idler gear 35, which latter engages a gear 36 carried on the forward end of a shaft 37 which is journaled in the work-supporting carriage 12, all of said gears being enclosed within the housing 33. The shaft 37 carries a worm gear 38 which is engaged by a worm 39, the latter being suitably rotated by the driving motor, not shown.

The worm 39 is arranged to be released from connection with the gear 38 or to be engaged therewith by mechanism similar to that fully disclosed in Patent No. 1,665,160 granted to Einstein (one of the present inventors), Peaslee, and and Hass, on April 3, 1929. For the purposes of this application, it will be suflicient to note that the crossfeed movement of the work-supporting member is procured while the worm and worm gear are connected together and that the crossfeed is discontinued by separation of said worm and gear. Referring to Fig. 9, which shows the structure by which the worm 39 is held in engagement with the gear 38, said worm is journaled in a bracket 40 pivotally supported by trunnions 41 provided by a housing 42, the latter depending from the work-supporting carriage 12. The shaft 43 on which the worm 39 is secured is connected by a universal joint, not shown, to the drive shaft 44 by which said worm is actuated, said joint being in alinement with the trunnions 41. The bracket 40 has a depending lug 45 in which a spring pressed plunger 46 is slidable and the plunger carries on the end thereof a roll 47 which engages with a cam 48 secured to a shaft 50' journaled in bearings provided by the housing 40. The shaft 50 also carries an arm 51 which, upon rocking movement, procures a swinging movement of the cam 48 and subsequent elevation of the worm 39 about the trunnions 41 as an axis into engagement with the worm gear 38, said worm being held in, engagement. with the gear by a solenoid 52, which, when energized, attracts the arm 51 and maintains it in raised position. Deenergization of the solenoid 52 will release the arm 51, allowing the latter to drop under the influence of gravity, thereby withdrawing the cam 48 from engagement with the roll 4'7 to allow the worm 39 to drop away from the gear 38.

The worm 39 is manually moved into engagement with the worm gear 38 by the mechanism shown in Figs. 3 and 9. The shaft 50 is provided with an arm 53, the free endlof which is connected by a link 54 to an arm 55 secured to a shaft 56 journaled in the work-supporting carriage. The free end of the shaft 56 projects beyond the front of the carriage through the housing 33 and has a handle 57 secured thereto so that movement of said handle procures rocking movement of the shaft 50 and consequent movement of the worm engagement therewith.

Upon separation of the worm from the worm gear at the end of the crossfeed movement, said movement is retracted. To this end, a pulley 58 .I O into engagement with the worm gear or out of on the shaft 3'! is connected by a flexible member 60 to a weight 61 vertically movable in a bracket 62 secured to the under side of the work-supporting carriage. During the crossfeed movement, the rotation of the shaft 3'7 procures elevation of the weight 61 and upon disconnection of the worr'nfrom the worm gear, the weight 61 procures a movement of the shaft 3'7 in the direction opposite to thatprocured by the worm 39, thereby retracting the crossfeed movement and separating the workpiece radially from the grinding wheel.

The above mechanism is all old and well known and does not, of itself, form a part of the present invention, which latter involves the attainment,

in connection with similar grinding machine instrumentalities, of the novel and useful results above set forth. According to the invention, the grinding operation is controlled by a gauge having a point which is arranged to contact with the surface of the grinding wheel at a predetermined point in the grinding operation, said gauge, upon contact with the grinding wheel, procuring a change in the grinding operation.

Referring now to Figs. 5, 6, '7 and 8 which show the novel gauge structure, the housing 27, in which the regulating wheel shaft is journaled, has a projecting portion 63 to which a member 64 is secured for supporting the gauge structure. A dove-tailed guide 65 on the member 64 provides a support for a slide 66 which is adjustable horizontally relative to the member 64 by an adjusting screw 6'7, the latter engaging a threaded bore 68 in the member 64. The adjusting screw is held against longitudinal movement in the slide 66 by a plate 69 which is secured to the member 66 and extends between a collar '70 and a split collar '71 on the screw, both said collars being secured against longitudinal movement on the screw 6'7. The split collar '71 is adjacent the head '71 of the screw and is angularly adjustable on the screw 6'7, being'secured against rotation by a clamping screw '72. Said split collar also carries a projecting arm '73 having an adjusting screw '74 therein, which is in a position to engage with'a pin '75 on the plate 69, said pin, in conjunction with the screw '74, limiting the rotation of said head and accordingly the rotation of the screw 6'7, and providing for accurate adjustment of the slide 66 by the turning of the screw 74 in the collar.

The slide 66 has an upwardly extending portion '76 which provides at the upper end thereof a horizontal offset portion 7'7, the upper surface of which is provided with a slot '78 to permit horizontal adjustment of a supporting arm therein, said arm being secured in adjusted position by a clamping bolt 81. The arm 80 projects forwardly of the portion '77 and receives in the free end thereof the upper end of a housing 82 which is secured to said arm 80 by a nut 83. The housing is mounted to depend from the arm in a plane substantially tangent to the forward surface of the regulating wheel, as shown in Fig. '7, and a pendulum or depending arm 84 is supported within the housing by pivots 85 adjacent the upper end thereof. The lower end of the pendulum 84 is bifurcated and one arm 86 thereof projects below the housing 82 and carries a gauge point 8'7, the end of which is provided with a diamond or other hard substance for engagement with the grinding wheel 8. The pendulum 84 has a second arm 88 which is movable within the housing 82 and is shielded from the opening through which the arm 86 projects by a baffle plate 90. Said arm 88 carries a contact point 91 on the lower end' thereof for engagement with a stationary contact 92 secured to the housing, said contacts 91 and 92 controlling the circuit by which the solenoid 52 is energized. The contact 91 is electrically connected through the pendulum 84 and a spring arm 93 which is secured to the housing to a bolt 94 insulated from said housing, the latter providing a connection for the power supply as will hereinafter appear. The pendulum 84 normally hangs freely by gravity within the housing and its position is adjusted by a set screw 95 projecting through the housing and engaging with the pendulum, said set screw being so adjusted that the gauge point 8'7 is in a proper position for engagement with the grinding wheel at the desired point in the grinding operation. In this position of the pendulum, the contacts 91 and 92 are slightly spaced from each other. The center of gravity of the pendulum is varied somewhat to provide for a greater sensitivity of the pendulum, as desired, by adjustment of a cross-bolt 96 in said pendulum. The housing also carries a solenoid 97 which, upon contact of the grinding wheel and the gauge point, is energized to procure attraction of the arm 84, thereby maintaining the contacts 91 and 92 in engagement and maintaining the gauge point 8'7 out of engagement with the grinding wheel. It will be apparent that,"by adjustment of the slide 66 on the member 64, and by adjustment of the arm 80 on the horizontal portion '77, the gauge point 8'7 may be adjusted to the desired position relative to the regulating wheel and in predeterminedrelation thereto for engagement with the grinding wheel when the workpiece has reached a predetermined size. In the construction shown, the gauge point is located in the common tangent plane of the surface of the workpiece and the grinding wheel and is also in the plane defined by the axes of the grinding wheel and the regulating wheel so that the finished workpiece has a shell thickness between the outer and inner surfaces thereof which corresponds precisely to the spacing of the gauge point from the periphery of the regulating wheel. The shell thickness of successive workpieces will always remain equal independently of the external diameter of the workpieces, since the gauge operates as a thickness determinator when the workpiece is mounted for centerless grinding. It will also be noted that each successive workpiece is reduced to the same desired size independently of the wear on the grinding wheel since the size of the workpiece isdetermined by the cutting surface of the grinding wheel independently of the diameter thereof.

The wiring diagram by which the crossfeed movement is discontinued upon engagement of the grinding wheel with the gauge point 87 is shown in Fig. 10. Power for the driving motor 98 which actuates the worm 39 is supplied from any suitable source. One terminal of the motor is connected to the source by a lead 99, and a lead 100 connects the other terminal of the motor to a switch 101, the other terminal of the latter beingconnected by a lead 102 to the source. The switch 101 is in the normal open position shown when the worm 39 is out of engagement with the worm gear, and is closed when the worm is moved into operative position, this latter being procured manually, as above stated, by the handle 103 which is diagrammatically shown in Fig. 10 as connected directly to the worm 39, but corresponds to the handle 57 and the arm 51. One

terminal of the solenoid 52 is connected by a lead 104 to the lead 99 and the other terminal of the solenoid is connected by a lead 105 to the lead 100, said solenoid and the motor 98 being thus in parallel relation in the circuit. As the worm 39 is moved into operative positionby the handle 57 .(handle 103 of Fig. 10), the switch 101 is closed,

with the grinding wheel 8 releases the worm 39 r from the worm gear 38. Referring again to Fig. 10, the bolt 94, which is electrically connected to the gauge contact 91 is connected by a lead 106 to the lead 100 through a resistance coil 107 and the stationary contact 92 is connected by a lead 108 to one terminal of the solenoid 97, the other terminal of which is connected by a lead 109 to the lead 99. This latter circuit, which is through the resistance 107, the gauge contacts 91 and 92, and the solenoid 9'7, comprises a secondary circuit which, upon being closed, by connection oi the contacts 91 and 92 momentarily deenergizes the solenoid 52, thereby releasing the arm 51 and allowing the worm to drop away from the worm gear. This movement of the worm away from the worm gear also opens the switch 101 to discontinue the rotation of the motor 98.

In the operation of the machine, the work-supporting carriage is moved longitudinally of the base to position the grinding wheel within the bore of the workpiece, this movement being procured by manual shifting movement of the lever 25, the work-supporting carriage being brought to rest in the operative position, as above pointed out, by engagement of the reversing dog 21 with the lever 23. The crossfeed movement is then initiated by movement of the worm into engage- 'ment with the worm gear, this latter being procured by rocking movement of the handle 57. Movement of the worin gear into operative position closes the switch 101 to complete the circuit through the motor 98, said motor procuring rotation of the worm 39. Closing of the switch. 101 also energizes the solenoid 52 to maintain the worm in operative engagement with the worm gear by attraction of the arm 51 (the handle 103 of Fig. 10). The crossfeed movement then continues until the grinding wheel engages and rocks the pendulum 84 to bring the contacts 91 and 92 into engagement. This engagement closes a circuit through the resistance coil 107, thereby momentarily deenergizing the solenoid 52 to release the arm 51 and allow the worm 39 to drop away from the worm gear. At the same time, the solenoid 97 is energized to attract the pendulum 84 and maintain the gauge point 87 away from the periphery of the grinding wheel. As the worm falls away from the worm gear, the crossfeed movement is retracted by the weight 61 which returns the cross-slide to the original position in readiness for a subsequent grinding operation. Before the subsequent grinding operation takes place, the pendulum 84 is returned to gauging position in whichthe contacts 91 and 92 are separated by opening of a manually controlled switch 110 in the lead 102 which breaks the circuit through the solenoid 97.

A modified wiring diagram for the machine is shown in Fig. 11. In this figure, the driving motor 98 for the worm 39' is connected by a lead 111 to the negative side of the source or power power. The solenoid 52' is connected in parallel with the motor 98 by a lead 114 which connects one terminal of the solenoid 52' to the lead 111 and a lead 115 connects the other terminal of the electromagnet to one terminal of a switch 116, the other terminal of which is connected by a. lead 117 to the lead 112, the circuit through the motor 98' and the solenoid 52' comprising the primary circuit. y

In the secondary circuit, the switch 116 is controlled by an electromagnet 118, one terminal of which is connected by a lead 120 to the lead 112 and the other terminal of which is connected by a lead 121 to the bolt 94' which, as above stated, is electrically connected to the gauge contact 91'. The stationary contact 92' is connected by a lead 122 to the solenoid 97' and the other terminal of thelatter is connected by a lead 123 to one terminal of a switch 124 which is controlled by an'electroniagnet 125 and is normally in the closed position shown. The opposite terminal of the switch 124' is connected by a lead 126 to the leadlIl. The electromagnet 125 has one terminal connected to the lead 112 by a lead 127 and the opposite terminal is connected by a lead 128 to a stationary contact 130 provided in a switch box 131. The contact 130 is arranged to be connected with a contact 132 by a movable switch member 133 which latter when in normal position is out of engagement with the contacts 130 and 132 and is heldin the inoperative position shown by a spring pressed plunger 134. The switch member 133 has an upwardly extending arm 135 which, in the diagrammatic showing in Fig. 11, is positioned for engagement with the lower end of the handle 103' for actuation thereby, as the worm 39' .moves into or out of engagement with the worm gear. The circuit through the switch 133 is completed by a lead 136 which connects the contact 132 to the lead 111. In the discussion of "the modified wiring diagram, the solenoids 52"and 97', the contacts 91 and 92', the bolt 94 and other members indicated by prime reference numerals correspond to the solenoids 52 and 97, the contacts 91 and 92, bolt 94 and similar members of the structure above disclosed.

The switch box 131 in the actual construction of the machine is carried by a bracket 137 secured to .the housing 42 and supporting said switch box' so that the arm 135 on the switch member 133 is in a position for engagement with the arm 51 -as the latter is moved from the inoperative position shown into the operative position in engagement with the solenoid 52.

In the operation of a machine connected as shown in the wiring diagram of Fig. 11, the crossfeed movement is procured by closing of the switch 113 which procures energization of the solenoid 52 and accordingly attraction of the arm 51 (the handle 103 of Fig. 11) to raise the worm 39 into engagement with the worm gear 38, the" movement of the arm 51 into worm elevating position being accomplished by manual rocking of the handle 57, Figs. 2 and 3. At this time, the switch 116, is in the normal closed position shown, and the switch 124 is also closed to procure rotation of the worm and thus a crossfeed movement of the work-support. The crossfeed mogyement continues until the grinding wheel comes in contact with the gauge point 87', thereby :rocking the pendulum 84' and procuring engagement of the contacts 91' and 92'. This engagement closes the circuit through, and energizes, the electromagnet 118 to open the switch 116, thereby disconnecting the circuit through the solenoid 52' and releasing the worm 39, so that at thistime the gauge contacts 91 and 92 are held in engagement by the solenoid 97, thereby maintaining the switch 116 open and thus the circuit through the electromagnet 52' open.

After an unground workpiece has been placed in the work-supporting member in readiness for a subsequent grinding operation, the worm 39 is returned to operative engagement with the worm gear 37 through manual movement of the arm 51 by the handle 57. This movement of the arm 51 procures a. clockwise rocking movement of the switch member 133 into engagement with the contacts 130 and 132, thereby momentarily closing the circuit through the electromagnet' 125 to open the switch 124, thereby breaking the circuit through the solenoid 9'7 to'allow the gauge contacts 91' and 92' to separate, the pendulum 84' then returning to gauging position, as will be apparent. Separation of the gauge contacts 91' and 92' deenergizes the electromagnet 118 so that the switch 116 returns to the closed position shown for energization of the solenoid 52' to maintain the worm and worm gear in operative position until the grinding wheel again comes in contact with and actuates the gauge point 87' during the'crossfeed movement.

In the modification of Figs. 12 and 13, the novel gauge structure is shown in connection with an external grinding machine. In this construction, the cylindrical workpiece 138 is mounted for rotation between centers 140 and 141 which are carried by a carriage 142 mounted for longitudinal reciprocation on ways 143 provided by the base of the machine, the workpiece being rotated in any desired manner. The grinding wheel 144 is mounted on a shaft 145 journaled in a crossslide 146, the crossfeed movement of which is procured in a manner similar to that ,disclosed in the construction of Figs. 1 to 4 inclusive. It is sufllcient to note that a crossfeed screw 14! engages a threaded nut 148 in the cross-slide and is rotated from a shaft 150 through spur gears 151 in a housing 152 secured to the base of the machine, said screw 14'? and" shaft 150 being journaled in sad housing. worm gear 153 whichis engaged by a worm 154, said gear and worm corresponding to the gear 38 and worm 39 of the construction first described.

The gauge structure in this modification is' mounted on the base of the machine and is precisely the same as the gauge structure above disclosed, the slide 66 being secured in this construction to the member 64, which latter'is secured to a portion of. the reciprocatory carriage 142. The gauge point 87 is in a position for engagement with the periphery of the grinding wheel in the common tangent plane of the grinding wheel and workpiece and closely adjacent to the end of said workpiece. Upon engagement of' the grinding wheel 144 with the gauge point 87, the worm 154 is separated from the worm gear The shaft 150 carries a 153 in the manner above disclosed, the wiring dia-' gram of either Fig. 9 or Fig. 10 being used for controlling the movements in this modification. The crossfeed movement is retracted, in this construction, by a weight 155 corresponding to the weight 61 above.

It will be noted that the sensitivity of the pendulum controlled may be adjusted by adjusting the position of the pivotal supports of said pendulum toward or away from the common vertical tangent plane of the grinding wheel and the workpiece. Adjustment of the pivot pins 85 forwardly of the machine, and corresponding adjustment of the set screw for positioning the contact 87 in the proper relation, will shift the center of gravity of said pendulum relative to the contact 87 so that a more positive engagement of the contact with the wheel is necessary for actuating the pendulum. Conversely, adjustment of the pivot pins 85 rearwardly of the machine will shift the center of gravity of the pendulum rearwardly relative to the gauge contact and, the set screw 95 being-properly adjusted for positioning of the gauge contact, only a slight engagement between the wheel and gauge contact is necessary for actuating the pendulum.

From the foregoing, it will be noted that the invention resides in a novel grinding machine,

incorporating a gauge which is adapted to contact with the surface of the grinding wheel so that the size of the workpiece is determined by the member that wears, each successive workpiece accordingly being reduced to the same predetermined size independently of the reduction in size of the grinding wheel. vThe gauge is in contact with the grinding wheel only instantaneously at the completion of each grinding operation and the wear on said gauge is accordingly so slight that it may be ignored. The gauge is immediately withdrawn from contact with the grinding wheel as soon as the latter comes into engagement therewith, thereby avoiding any appreciable wear on said gauge. The invention is particularly useful in centerless internal grinding in that it is possible by this construction to provide successive workpieces, the shell thickness of which is constant independently of the external diameter of the workpiece and the shell thickness, as will be apparent, is determined by the "spacing of the gauge point radially from the periphery of the regulating wheel. 1

We claim,

1. In a grinding machine, a grinding wheel, a centerless work-support comprising a regulating wheel engageable with the periphery of a workpiece, and a pressure wheel to maintain the workpiece in engagement with said regulating wheel, the latterby its rotation procuring )tation of said work piece, a gauge in a position for engagement with the periphery of the grinding wheel along an element of said wheel which is in engagement with the workpiece, said "gauge being in predetermined relation to said regulating wheel. 1

2. In a grinding machine, a grinding wheel, a work-supporting member comprising a. rotatable regulating wheel engaging the periphery of a workpiece to procure rotation thereof, a worksupport spaced from said regulating wheel, and a pressure wheel opposed to said regulating wheel to maintain said workpiece in engagement therewith, means to procure a crossfeed movement of said grinding wheel relative to the workpiece in said work-supporting member, a gauge mounted in predetermined relation to the regulating wheel and engageable with the periphery of said grinding wheel along the element of said wheel which is in contact with the workpiece, and means controlled by said gauge to procure a change in the grinding operation.

3. In a grinding machine, a grinding wheel, a work-supporting member comprising a rotatable regulating wheel engaging the periphery of a workpiece to procure rotation theerof, a worksupport spaced from said regulating wheel, and a pressure wheel opposed to said regulating wheel to maintain said workpiece in engagement therewith, means to procure a crossfeed movement of said grinding wheel relative to the workpiece in said work-supporting member, a gauge mounted in predetermined relation to the regulating wheel and engageable with the periphery of said grinding wheel along the element of said wheel which is in contact with the workpiece, and means controlled by said gauge to the crossfeed movement.

4. In a grinding machine, a grinding wheel, a work-supporting member comprising a rotatable regulating wheel engaging the periphery of a workpiece to procure rotation thereof, a work support spaced from said regulating wheel, and a pressure wheel opposed to said regulating wheel to maintain said workpiece in engagement therewith, means to procure a crossfeed movement of said grinding wheel relative to the workpiece in said work-supporting member, a gauge mounted in predetermined relation to the regulating wheel and engageable with the periphery of said grinding wheel along the element of said wheel which is in contact with the workpiece, and means operable upon engagement of said wheel and gauge to procure a change in the grinding operation.

5. In a grinding machine, a grinding wheel, a work-supporting member comprising a rotatable regulating wheel engaging the periphery of a workpiece to procure rotation thereof, a worksupport spaced from said regulating wheel, and a pressure wheel opposed to said regulating wheel to maintain said workpiece in engagement therewith, means to procure a crossfeed movement of said grinding wheel relative to the workpiece in said work-supporting member, a gauge mounted in predetermined relation to said regulating wheel and engageable with the periphery of said grinding wheel in the common tangent plane of said grinding wheel and the surface being ground, and means operable upon engagement of said wheel with the gauge to procure a change in the grinding operation.

6. In a mechanism of the character described, the combination with a grinding machine having a bracket ailixed thereto, of a slide bracket thereon having precision means for adjusting its relative position thereto, a housing adjustably supported on an arm of said slide bracket, a pendulum pivotally suspended in said housing, shiftable weight means on said pendulum, adjustable means preventing oscillation of said pendulum beyond a predetermined point in one .direction, a feeler on said pendulum for contact with the grinding means of said grinding machine, said feeler being in the line of contact between the grinding means and the work, and an electrical circuit operated by the oscillation of said pendulum to discontinue the operative,

advance of the grinding means.

7. The combination with a grinding machine having relatively infed grinding and'work-supporting meansthereon. of a bifurcated pendulum procure cessation of sizing arm adjustably supported thereon, a feeler on one bifurcation of said arm adapted to be placed in the line of contact between the grinding means and the work, an electrical contact on the other bifurcation, baiile means protecting said electrical contact from action by the coolant, and an electrical'circuit operable by the action of said sizing arm for discontinuing the relative feeding action of said grinding and work-supporting means.

8. In a grinding machine, a grinding member mounted for movement toward and from the work, an oscillatable sizing mechanism in the path of said grinding member, a circuit operative by the oscillation of said sizing mechanism for controlling the approach of the grinding member to the work, said circuit including spaced contacts and also means effective on initial engagement of the contacts for positively retaining them in circuitcompleting engagement.

9. In a device of the character described, a grinding wheel mounted for movement toward and from the work, a sizing arm supported in the path of said grinding wheel, said arm having a feeler in the line of .contact between said grinding wheel and the work, a circuit operative by contact of said feeler and said grinding wheel for stopping the infeed action of said grinding wheel, said circuit including spaced contacts and also means effective on initial engagement of the contacts for positively retaining them in operative engagement.

10. In a device of the character described, a grinding wheel mounted for feeding and retractive movement relative to the work, the grinding wheel and the work being also mounted for relative transverse movement the one to the other, a sizing feeler in the line of contact between the wheel and the work, a control circuit including an oscillatable circuit completing member, said member supporting said feeler and being oscillatable by contact of said feeler and said wheel, and means for positively locking the member against oscillation effective on initial completion of the circuit, said control circuit, when completed, serving to stop the feeding movement of the grinding wheel.

11. In a grinding machine, the combination with a rotary grinding wheel and an opposed workpiece adapted to be operated upon thereby, of means for eflecting a feeding movement of one of said first two parts with respect to the other and means for accurately determining .the size of the finished workpiece, comprising apendulum supported in fixed relation to the workpiece and having a feeler contact for engagement with the periphery of the rotating grinding wheel during therelative advance of the work and grinding wheel one toward the other, whereby contact of the grinding wheel with the pendulum will effect an oscillation thereof, and an electrical control circuit for discontinuing the feeding movement completable on oscillation of the pendulum, said circuit including electromagnetic means forretaining the pendulum in retracted positionwhen initially oscillated by the grinding wheel.

12. A sizing mechanism for use in conjunction with a grinding machine or the like including a pendulum member, means supporting the pendulum for gravitational urge in the direction of the grinding wheel, means for limiting the movement of the pendulum in said direction, and an electric-control circuit completable by reverse oscillation of the pendulum as by engagement of the rotary surface of the grinding wheel there'- with, said control circuit including electromaga netic means for retaining the pendulum in circuit closing position and retracted as respects the grinding wheel.

13. The combination with a grinding machine including means for rotatably supporting a workpiece, a rotary grinding wheel for operation on the workpiece and means for effecting relative feeding movement of one of said parts with respect to the other for desired removal of stock from the workpiece by the grinding wheel, precision means for limiting said feeding movement including a pendulum having a feeler adapted to contact the operative surfaceol the grinding wheel, means supporting the pendulum for oscillatory movement in a direction toward and from the periphery of the grinding wheel, means for adjusting the position of the pendulum to aline the feeler point with the common tangent plane of the work and grinding wheel in their common radial plane, but offset or laterally dis-j placed as respects the workpiece, whereby the feeler will engage a laterally projecting portion of the grinding wheel surface in exact similarity with the contact of the work surface being operated upon by the grinding whee1, said feeler being gravitationally urged in the direction of the grinding wheel, means for limiting the swinging movement of the pendulum in the direction of the grinding wheel, and an electric control circuit efiective to discontinue relative feeding movement of the work and grinding wheel coma pletable on oscillation of the feeler in'the direction away from the grinding wheel whereby the kick of the wheel surface against the feeler on inception of engagement of-the parts will oscillate the pendulumto determine the size of the workpiece.

14. The combination with a grinding machine including work-supporting means, an opposed grinding wheel and mechanism for procuring a relative. feeding movement of the parts, of a feeler device for determining the operative effect of the feeding mechanism including an oscillatable member having a feeler for engagement by the grinding wheel surface, said oscillatable member forming a part of an electric control circuit and adapted, when oscillated iii a direction away from the grinding wheel, to complete the control circuit, and electrically actuated means for automatically securing the oscillatable member in retracted position on completion of the control circuit.

15. The combination with a grinding machine having relatively infed grinding and work-supporting means thereon, of a bifurcated pendulum sizing arm adjustably supported thereon, a feeler on one bifurcation of said arm adapted to be placed in the line of contact between the grind-v ing means and the work, an electrical contact on the other bifurcation, baflie means protecting said electrical contact from action by the coolant, and an electrical circuit operable by the action of said sizing arm for procuring a change in the grinding operation.

16. In a device of the character described, a grinding wheel mounted for movement toward and from the work, a sizing arm supported in the path of said grinding wheel, said arm having a feeler in the line of contact between said grinding wheel and the work, a circuit operative by contact of said feeler and-said grinding wheel for procuring a change-in the grinding operation, said circuit including spaced contacts and also means eifective on initial engagement of the contacts for positively retaining them in operative engagement. I

1'7L'In a grinding machine, the combination with a rotary grinding wheel and ,an opposed workpiece adapted to be operated upon thereby, of means for effecting a feeding movement of one of said first two parts with respect to the-other and means for accurately determining the size of the finished workpiece, comprising a pendulum supported in fixed relation to the workpiece and having a feeler contact for engagement with the periphery of the rotating grinding wheel during the relative advance of the work and grinding wheel one toward the other, whereby contact of the grinding wheel with the pendulum will effect an oscillation thereof, and an electrical control circuit completable on oscillation of the pendulum for procuring a change in the grinding operation, said circuit including electromagnetic means for retaining the pendulum in retracted position when initially oscillated by the grinding wheel.

18. In a device of the class described, the combination of a bed, a grinding wheel rotatably mounted thereon, means for rotatably supporting a workpiece to be operated upon by the grinding wheel, means for effecting a relative feed between the work and wheel, and means for interrupting the relative feed for stopping same when the work is reduced to the desired size, said means comprising a pivotally mounted pendulum, a contact member on the pendulum for engagement with the grinding wheel, a primary electrical circuit for controlling the feed mechanism, a secondary electrical circuit extending from the primary circuit, and contacts on the pendulum adapted to complete the secondary circuit by the swinging of the pendulum in one direction for interrupting the primary circuit and retaining the pendulum in the primary circuit interrupting position.

19. In a device of the class described, the combination of a bed, a grinding wheel rotatably mounted thereon, means for rotatably supporting a workpiece to be operated upon by the grinding wheel, means for effecting a relative feed between the work and wheel, means for interrupting the relative feed for stopping same when the work is reduced to the desired size comprising a pivotally mounted pendulum, a contact member on the pendulum for engagement with the grinding wheel, a primary electrical circuit for controlling the feed mechanism, a secondary electrical circuit extending from the primary circuit, contacts on the pendulum adapted to complete the secondary circuit by the swinging of the pendulum in one direction for interrupting the primary circuit and retaining the pendulum in the primary circuit interrupting position, and means for automatically retracting the grinding wheel from the work upon discontinuance of the feed.

20. A sizing mechanism for use with grinding machines comprising a rotatable grinding wheel, a rotatable work-support, a feed mechanism for effecting a relative radial approachof the grinding wheel and work-support, means for interrupting the feeding movement comprising a pivotally mounted pendulum arm, a feeler on the arm spaced a predetermined distance from the axis of the work representative of the exact between the work and wheel to aline the said wheel with the ofiset work sizing feeler.

21. In a sizing device for use with a grinding machine, the combination of a bed, a grinding wheel rotatably supported thereby, a work-sup- Port on the bed for supporting a workpiece during rotation, means for effecting a relative feed of the work and grinding wheel one toward the other in a plane common to both the work and wheel in a radial direction, an electrical control circuit for controlling a portion of the feeding means, and means controlling the electrical circuit and positioned in the feeding plane for engagement with the grinding wheel .to complete the electrical circuit when the work and grinding wheel have approached one another an amount to reduce the work to the desired finished size.

22. In a grinding machine, the combination of a rotatable grinding wheel, a work-support for rotatably supporting a workpiece adjacent the grinding wheel, means for feeding the work and wheel toward one another in a plane radially common to both work and grinding wheel, a. separable connection in the feeding mechanism, an electrical circuit including spaced contacts normally separated to break the electrical circuit for controlling the separable connection, said contacts lying substantially in the plane of feed of the work and grinding wheel and adapted to be actuated toward one another during the feeding movement for completing the electrical circuit and breaking the separable connection in the feeding means, a secondary electrical shunt circuit, and electromagnetic means in said circuit energizable upon completion of the electrical circuit by the feeding means for holding said electrical circuit complete.

23. In a grinding machine, the combination of a rotatable grinding wheel, a work-support for rotatably supporting a workpiece adjacent to the grinding wheel, means for feeding the work and wheel toward one another in a plane radially common to both work and grinding wheel, a separable connection in the feeding mechanism, an electrical circuit including spaced contacts normally separated to break the electrical circuit for controlling the separable connection, said contacts lying substantially in the plane of feed of the work and grinding wheel and adapted to be actuated toward one another during the feeding movement for completing the electrical circuit andbreaking the separable connection in the feeding means, a secondary electrical shunt circuit, electromagnetic means in said circuit energizable upon completion of the electrical circuit by the feeding means for holding said electrical circuit complete, and means for retracting the work and grinding wheel from one another upon interruption of the feeding" means.

24. In a grinding machine, a grinding wheel, a work-supporting member comprising a rotatable regulating wheel engaging the periphery of a workpiece to procure rotation thereof, a worksupport spaced from said regulating wheel, and

a pressure wheel opposed to said regulating wheel to maintain said workpiece in engagement therewith, means to procure -a crossfeed movement of said grinding wheel relative to the workpiece in said work-supporting member, means to procure a relative translatory movement of the rinding wheel over the surface of the workpiece, a gauge mounted in predetermined relation to the regulating wheel and engageable with the periphery of said grinding wheel along the element of said wheel which is in contact with said workpiece, said wheel engaging said gauge during the translatory movement which carries a portion of the wheel beyond the edge of the workpiece and into alinement with the gauge, and means operable upon engagement of said wheel and gauge to procure a change in the grinding operation.

25. In a grinding machine,.a grinding wheel, a work-support, a feed mechanism for effecting a relative radial movement between the grinding wheel and a workpiece in the work-support,

of rotation of the workpiece in the work-support,

said feeler lying in the plane of the line contact 01 the grinding wheel with the workpiece and offset relative to the work for engagement with the periphery of the grinding wheel.

26. In a grinding machine, a grinding wheel, a work-support, a feed mechanism for effecting a relative radial movement between the grinding wheel and a workpiece in the work-support, a sizing mechanism comprising a pivotally mounted pendulum arm, a feeler on the arm spaced a predetermined distance from the axis of rotation of the workpiece in the work-support, said feeler lying in the plane of the line contact of the grinding wheel with the workpiece and offset relative to the work for engagement with the periphery of the grinding wheel, and means for procuring a relative traversing movement between the wheel and the work-support for positioning said wheel in alinement with the feeler.

SOL EINSTEIN. CLEMENT BOOTH. 

